The overexpression of the CD44H isoform, which contains a specific binding domain to HA in different carcinomas, gliomas, and non-Hodgkin’s lymphomas [10], indicates that CD44-HA interactions can be exploited to capture circulating tumor cells (CTC) for diagnostic purposes, though some of the CD44 isoforms do not bind HA [10]. This evidence concerns the gene CD44 and central nervous system cancer.